In a certain conventional compressor used for air-conditioning of automotive vehicles, means are provided for adjusting the compression capacity or performance as a function of occasional cooling demand. The present inventor has proposed a compressor of this type in which, as shown in FIG. 9, an inner housing 62 movable axially of a rotary shaft is mounted in the rear housing 61 for providing a pressure chamber 63 between the inner surface of the rear housing 61 and the rear surface of the inner housing 62, a valve plate 64 is secured to the open front end face of the inner housing 62, and wherein a changeover valve 65 is provided for selective application of a high or discharge pressure or a low or suction pressure to said pressure chamber 63 to enable the compressor capacity to be switched between 100% value and 50% value to eliminate any unnecessary compression when the smaller compressor capacity is required.
However, with such swash plate compressor, a suction chamber 66 and a discharge chamber 67 are provided in the central and radially outward portions of the inner housing 62. Thus, when the front housing 68 and the rear housing 61 are secured to the front and rear cylinder blocks 69, 70 by through-bolts, the latter must be passed through the high-pressure discharge chamber 67, thus posing a serious sealing problem. Thus it is necessary, after securing the cylinder blocks 69, 70 to the front housing 68 by through-bolts 71, to fixedly clamp the rear cylinder block 70 and the rear housing 61 together by further clamp bolts 72, which are arranged radially outwardly of a sealing O-ring 73, as shown in FIG. 10, with consequent increase in the outside diameter of the compressor.